Electrosprayed droplet impact/secondary ion mass spectrometry
Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu, 400-8511, Japan
Corresponding author: a email@example.com
Published online: 25 October 2005
A new ionization method, electrosprayed droplet impact ionization (EDI), has been developed for mass spectrometry. The charged droplets formed by electrospraying 1 M acetic acid aqueous solution are sampled through an orifice with a diameter of 400 μm into the first vacuum chamber, transported into a quadrupole ion guide and accelerated by 10 kV after exiting the ion guide. The m/z of the primary droplet projectiles range from 10 000 to 50 000. The droplets impact on a dry solid sample deposited on a stainless steel substrate. No matrix was used for the sample preparation. The secondary ions formed by the impact are transported to a second quadrupole ion guide and mass-analyzed by an orthogonal TOF-MS. Intense molecular-related ions are detected for drugs, amino acids, peptides and proteins. EDI is found to be very sensitive to molecules present near the surface of the sample.
PACS: 34.50.Dy – Interactions of atoms and molecules with surfaces; photon and electron emission; neutralization of ions / 36.40.Gk – Plasma and collective effects in clusters / 39.10.+j – Atomic and molecular beam sources and techniques
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006